Official controlling and hallmarking

All watch-cases in gold, silver, platinum or palladium, of foreign or local manufacture, sold in Switzerland, are subject to control and compulsory official marking.

Apart from watch-cases, that is for all other precious metal articles, and multimetal goods, the control procedure is optional.

A single official hallmark will be used for all precious metals and all fineness standards, the "head of a St. Bernhard dog":

The official hallmark bears the distinctive symbol of the Assay Office, which is positioned at the spot marked with an X.

 

Distinctive symbol: Biel/Bienne

B

  Chiasso

T

  Genève

G

  La Chaux-de-Fonds

C

  Le Noirmont

J

  Zürich

Z

https://www.ezv.admin.ch/content/ezv/en/home/topics/precious-metal-control/official-controlling-and-hallmarking.html